Vessel stopped by tangled mats of hyacinth

Tangled mats of water hyacinth delayed the arrival of an oceangoing ship at the Port of Stockton on Tuesday, further evidence that the exotic weed has potential to threaten business and commerce.

The Atlantic Rainbow, carrying a cement product from Japan, notified port officials over the weekend that it would be delayed because of hyacinth, Port Director Richard Aschieris said Tuesday.

Clearly, cargo ships are large enough to plow right through the weeds. The problem comes at night, when the ships’ radars sometimes cannot distinguish between the floating mats of hyacinth and dry land. That makes some pilots inclined to wait until daybreak before continuing up the channel to Stockton.

The Atlantic Rainbow pulled into port about 1 p.m. Tuesday. In this case, the delay was not severe — perhaps several hours, Aschieris said.

“But the port is always interested in being efficient,” he said. “These ships can cost tens of thousands of dollars every day. We want the ships to come in as quickly as they can, either load or unload and then get on their way to benefit the customer.”

The port has hired a contractor to mechanically remove hyacinth, but that work has focused on the area immediately around the port and, on Tuesday, the downtown waterfront.

These cargo ships must navigate the entire Delta to get to Stockton.

Hyacinth-related delays have occurred periodically in the past, but this was the first such delay this year, Aschieris said.

The current infestation seems to be the worst in recent memory, the port director said. He said the port is in discussions with the University of the Pacific and the University of California, Davis, for a hyacinth study that could help determine strategies to control the weed.

Aschieris said Tuesday’s delay reinforces the real potential impact of hyacinth, to both recreational boats and commercial ships.